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## Homework Statement

A Bi-metallic strip is straight at T= T

_{0}. It curves as it is heated up due to unequal expansion of two metals. The strip is made up of iron (a = 1.2e-5) and zinc (a = 3.1e-5). The question asks to calculate the bending angle when the original length of the strip is 100mm and with thickness of 1 mm.

## Homework Equations

The linear expansion equation: L = L

_{0}(1 + a(T

_{2}- T

_{0}))

## The Attempt at a Solution

The substituted equations: L

_{I}= (100)(1 + (1.2e-5)([tex]\Delta[/tex]T)

L

_{Z}= (100)(1 + (3.1e-5)([tex]\Delta[/tex]T)

From here I use the formula s = r[tex]\theta[/tex]

and get [tex]\theta[/tex] = (3.8e-3)([tex]\Delta[/tex]T)

I am not sure how to proceed from here because the question asks for a numerical answer but that seems impossible without the temperatures given.